Harnisch et al., U.S. Pat. No. 4,841,052 describe naphthalic acid imides useful as charge-regulating substances in electrophotographic toners.
Brana et al., U.S. Pat. No. 4,874,863 discloses anticancer bisnaphthalimides wherein the naphthalimides are linked by a straight chain or branched C.sub.4 -C.sub.10 -alkylene which is interrupted at one or two points in the chain by a secondary or tertiary amino group, where 2 nitrogen atoms may additionally be bonded to one another by an alkylene group. Brana et al., U.S. Pat. No. 4,874,863 does not disclose or suggest the unsymmetrical bis-imide compounds of the present invention. Moreover, the compounds of the present invention exhibit unexpected superior antitumor activity relative to the compounds specifically disclosed by Brana et al.
Ardecky et al. U.S. Pat. No. 5,086,059 discloses certain symmetrical bis-imide compounds. Ardecky et al. does not disclose or suggest the unsymmetrical bis-imide compounds of the present invention.
Sun PCT WO 92/17453 also discloses symmetrical naphthalimide compounds. Sun does not disclose or suggest the unsymmetrical compounds of the present invention. Moreover, the compounds of the present invention have unexpected improved solubility relative to the compounds of Sun.